Detecting means for stolen goods



Dec. 11, 1956 THOMPSON 2,774,060

DETECTING MEANS FOR STOLEN GOODS Filed June 15, 195E 62 68 12 65 Q INVENTOR.

Thoma-s1? T horn son nited tates DETECTING MEANS non sToLEN Goons Application June 15, 1953, Serial No. 361,575

9 Claims. (Cl. 340-258) This invention pertains to the actuation of electric circuits, and relates particularly to a novel method and apparatus for actuating an electric circuit from a remote position.

It is a principal object of the present invention to provide a method and apparatus for actuating an electric circuit from a remote position by means completely disconnected from the circuit or apparatus.

Another important object of this invention is the provision of a method and apparatus for actuating an electric circuit in response to the presence at a remote position of means which activate the apparatus.

A further important object of the present invention is to provide a method and apparatus for actuating an electric circuit for operating a lock, switch, and other devices by the presence at a remote position of a key which activates the apparatus.

A still further and important object of this invention is the provision of a method and apparatus for actuating an electric circuit for detecting stolen merchandise by the presence on the merchandise of means which, when placed at a remote position within the operative range of the apparatus, activates the latter to detect the theft.

Still another important object of this invention is the provision of a method and apparatus for actuating an electric circuit for detecting stolen merchandise by means attached to the merchandise in the form of a price tag or other similar conventional, and therefore inconspicuous, tag or label.

A still further object of the present invention is to provide apparatus for actuating an electric circuit from a remote position, which apparatus is of simplified construction and therefore inexpensive in cost and requires a minimum of maintenance and repair, and which is faithful in operation.

The foregoing and other objects and advantages of the present invention will appear from the following detailed description taken in connection with the accompanying drawing, in which:

Figure 1 is a diagrammatic view in elevation of a cash-iers counter and showing associated therewith apparatus embodying the features of the present invention for actuating an electric circuit for the purpose of detecting stolen merchandise;

Figure 2 is a schematic diagram showing one form of electrical circuitry for the apparatus of the present invention;

Figure 3 is a schematic diagram of a modified form of electrical circuitry adapted for use in the apparatus of the present invention;

Figure 4 is a plan view of one form of price tag adapted to carry one form of means by which to activate the apparatus of the present invention;

Figure 5 is a sectional view taken along the line 5-5 in Figure 4;

Figure 6 is a schematic diagram, partly in block form, illustrating a still further modified form of apparatus embodying the features of the present invention;

2,7id,6fi Patented Dec. 11, 1956 ice Figure 7 is a plan view of a modified form of price tag carrying the means for actuating the apparatus shown in Figure 6; and

Figure 8 is a plan view of an identification card having incorporated therewith means by which to activate the apparatus shown in Figure 6.

In its broad aspect, the method and apparatus of the present invention involves the actuation of an electric circuit by connecting to said electric circuit an oscillator of the type that is responsive to a tuned resonant circuit placed remotely from said oscillator but within the field thereof, whereby to cause the oscillator to change in potential, and then to utilize said change in potential to actuate the electric circuit.

Actuation of an electric circuit may be utilized to operate many dilferent types of devices, such as relays, solenoids, etc. These devices may, in turn, be utilized to operate other devices. For example, a solenoid may be utilized to operate various mechanical devices such as door locks, clutches, brakes, drive motors, etc. Relays may be utilized to control the operation of electric contact switches. Since the present invention functions basically to actuate an electric circuit, it will be apparent that the scope of the present invention is limited only to the extent that the actuation of an electric circuit is required to perform a given operation.

The method and apparatus of the present invention has been found particularly suited to the detection of stolen merchandise and is particularly adapted for that use by retail stores of various types in which it is practicable to provide exits of limited space. Referring particularly to Figure 1 of the drawing, there is shown a typical installation by which the method and apparatus of the present invention may be utilized to detect stolen merchandise. This installation includes a cashiers counter 10 supporting a cash register 11 and providing the usual space upon which the customer may deposit articles which he desires to purchase. A guide rail 12 is mounted in spaced relation to the counter 10 to form an aisle 13 through which the customers must pass for egress from the store. Mounted under the counter 19 and upon the guide rail 12 are duplicates of the apparatus of the present invention, said apparatus being designated generally by numeral 14.

Referring to Figure 2 of the drawing, the oscillator illustrated includes the antenna 20 connected through capacitors 21, 22 to the plate 23 and grid 24, respectively,

of the triode 25, the cathode 26 thereof being connected through the parallel combination of resistance 27 and capacitor 28 to ground. Capacitors 29 and 30 are arranged in series with each other and in shunt with the antenna 20, the connect-ion between said capacitors being grounded. Plate potential for tube 25 is provided through resistance 31, as shown.

The grid 24 of tube 25 is connected through choke coil 32 and potentiometer 33 to the grid 34 of amplifier tube 35. The cathode 36 of tube 35 is connected through resistance 37 to ground, while the plate 38 is connected for purposes of the present invention through relay 4% to a positive potential.

From the foregoing, it will be'understood that when a resonant circuit is placed within the field of the tank circuit comprising the antenna 20 and capacitors 29, 30 the drop in grid voltage functions to operate amplifier tube 35 to increase the plate current of the latter and thereby activate the relay 40.

It will be understood further that various modifications in the above described circuit may be provided to achieve the same results described above. For example, in Figure 3 of the drawing, the grid 41 of amplifier tube 42 is connected through potentiometer 43 to the plate 23 of tube 25- and through said potentiometer to a positive potential, as shown. In this arrangement to the merchandise.

the increased plate current in tube 25 resulting from placing a resonant circuit within the field of the tank circuit is utilized to operate amplifier tube 42, with the increased plate current therein activating the relay '40.

The relay 40 shown in Figures 2 and 3 of the drawing function to actuate a switch 44 arranged in series in an electrical circuit of a device to be operated, such as is indicated at 45 in using the apparatus for detecting stolen merchandise, the device 45 may be an alarm, in the form of a buzzer, an electric lamp or any other suitable means. The device 45 may also be a solenoid, for example, for actuating a door lock for private clubs or for defense plants, and for operating a clutch or a brake in various types of machinery or process equipment. In any of these instances it is required only that a tuned resonant circuit such as is indicated in Figure 4 be provided for intermittently operating the oscillator in accordance with the desired sequence of operation of the device 45.

Referring now to Figures 4 and 5 of the drawing, there is shown a preferred form of tuned resonant circuit adapted for use in activating the oscillator circuit and relay system described hereinbefore. This resonant circuit comprises an electrical conductor 59 formed in the shape of a spiral, with the ends 51, 52 thereof arranged in spaced relation. This resonant circuit may be formed in various ways, for example by bending a length of wire, or by painting an electrically conductive material upon a sheet of electrically non-conductive material, in accordance with the well-known practice of printed circuits. The resonant circuit illustrated is formed precisely so as to be tuned to the exact frequency of the oscillator.

For use of the apparatus in the detection of stolen merchandise, it is most convenient to mount the tuned circuit 50 upon a tag or other label adapted to be afiixed In the form shown in Figures 4 and 5, a price tag is formed of two sections 53 and 54 separated by a perforated line 55. The tag is made up of superimposed sheets which are ultimately glued together in well-known manner. Between the laminations of section 54 the tuned circuit 50 is conveniently secured so as to be completely concealed within the tag. Thus, when the merchandise is purchased the cashier merely removes the section 54 by tearing along the perforation line 55 as explained hereinafter.

A modified form of apparatus is illustrated in Figure 6. Therein is shown three oscillator devices 60, 61 and 62 each having a tank circuit including antenna 63, 64, 65, respectively, which tank circuits are each tuned to a diflFerent frequency of oscillation. Each oscillator is also connected to a separate relay 66, 67, 68, respectively, in the manner explained hereinbefore. Each relay is adapted to actuate a set of switch contacts 70, 71 and 72, respectively, arranged in series in the electrical circuit of a device 73 to be actuated.

For use with the apparatus of Figure 6, for example in the detection of stolen merchandise, the price tag illustrated in Figure 7 may be employed. This price tag is similar in construction to the tag shown in Figure 4, in that it comprises the two sections 53, 54 separated by the perforation line 55. However, concealed between the sheets of the tag section 54 are the three different lengths of electrically conducting material such as wire rod or the printed conductors described hereinbefore. These different lengths of electrically conducting material each comprises a tuned circuit 74, 75, 76, respectively, tuned to the exact frequency of the respective oscillators 60, 61, 62. Thus, when the three oscillators are placed with their respective antennas close together and the price tag carrying the three tuned circuits as placed within the field of the said oscillator antennas, the three relays will be actuated and the series switches closed to activate the circuit of the device 73.

Thus, it will be seen that in order to actuate the device 73 there must be present at one instant within the field of the antennas of the three oscillators the three tuned circuits 74, 75, 76. This arrangement insures against false activation of the device 73, since it is very improbable that a person will be carrying any articles of personal effects which might correspond electrically to all three of the tuned circuits. In this manner, the actuation of the device 73 can be assumed to be elfected only by the presence in the antenna field of the specially designed price tag such as is illustrated in Figure 7.

The apparatus of Figure 6 is also well adapted for use in actuating a door lock, such as in private clubs, defense plants, and other places where privacy or secrecy is to be maintained. For this purpose each person authorized to enter a restricted area is provided with an identification card 80, or a membership card, in which is concealed the tuned circuits 74, 75 and 76, substantially in the manner described hereinbefore. As a matter of additional security, these cards may be changed from time to time to add or subtract tuned circuits therefrom or to change the frequency characteristics thereof in order to render previous cards obsolete.

The operation of the apparatus described hereinbefore for use in detecting stolen merchandise is as follows: Each article of merchandise is provided with a label or price tag such as is illustrated in Figures 4 and 7, the same being applied to the merchandise in conventional manner. The price tags may be provided on their outer surface with the usual type of information, such as the store name, the stock number, a price code and a retail price. This information may be applied to both sections 53 and 54, whereby to provide a convenient check of sales for the store, since the section 54 is removed when the article is paid for at the cashiers counter.

When an article of merchandise is concealed upon a person or within carrying bags with the intention to steal the merchandise, the person is required to pass through the aisle 13 on his way from the store. Thus, when the person passes through the field of the cooperating pair of detection devices 14, the tuned circuit 50 concealed within the price tag secured to the merchandise impresses a load upon one or theother of the oscillator tank circuits and causes a change in potential to occur in the oscillator tube 25. This change in potential is utilized to activate the relay 40 in the manner purchased will not cause activation of the detecting de- V vice because such merchandise is placed upon the counter.

10 outside the field 90. Further, by removing the section 54 of the price tag when the article is purchased,

the customer may return to the store for the purpose of purchasing other articles without causing a false indication of the detecting device.

It will be apparent to those skilled in the art that various changes in structural details described hereinbefore may be made without departing from the scope and spirit of the present invention. For example, various types of oscillator circuits may be employed and various frequency levels of operation may be utilized as desired. Oscillator frequencies of from 300 to 400 megacycles, for example, are conveniently employed with the tuned circuit 50 shown in Figure 4, since at such frequencies this tuned circuit is approximately one inch in diameter. In the modification of Figure 6, oscillator frequencies in the range of about 5000 megacycles afiord the use of straight line tuned circuits, such as are shown in Figures 7 and 8, of approximately one inch in length. Thus, each of the oscillators may be constructed to operate on frequencies which permit the use of straight line tuned resonant circuits varying, for example, from about of an inch to about 1% inch. It will be understood, however, that other frequencies may be utilized as desired.

The tuned resonant circuits adapted to activate the oscillators may be provided in various forms, as indicated, and may be applied to various types of merchandise and other objects in various ways. the tuned resonant circuit may be applied directly to the goods, as by the technique of printed circuits, or they may be applied to wrappers or containers for the merchandise or to labels conventionally provided for such merchandise.

The foregoing and other modifications and changes may be made as will be apparent to those skilled in the art. Accordingly, it is to be understood that the foregoing description is merely illustrative of the invention and is not to be considered as limiting the scope thereof.

Having now described my invention and the manner in which the same may be used, what I claim as new and desire to secure by Letters Patent is:

1. Apparatus for actuating an electric circuit, said apparatus comprising an oscillator having an output radiation field projecting therefrom in a predetermined pattern and to a predetermined effective distance and being reactive only to a single tuned resonant circuit to change the potential of said oscillator, means forming a single tuned resonant circuit tuned to the frequency of the oscillator, and means connecting the oscillator to the electric circuit for actuating the latter when the resonant circuit is placed anywhere within the radiation field of the oscillator.

2. Apparatus for actuating an electric circuit, said apparatus comprising an oscillator reactive only to a single tuned resonant circuit to change the potential of said oscillator, an electrically non-conductive laminated card, an electrical conductor concealed within the card and forming a single tuned resonant circuit tuned to the frequency of the oscillator, and means connecting the oscillator to the electric circuit for actuating the latter when the resonant circuit is placed within the radiation field of the oscillator.

3. Apparatus for actuating an electric circuit for detecting stolen merchandise, said apparatus comprising an oscillator reactive to a single tuned resonant circuit to change the potential of said oscillator, means forming a resonant circuit tuned to the frequency of the oscillator, the resonant circuit being removably mounted on the merchandise, the oscillator being positioned so that the merchandise must pass through the oscillator field, and means connecting the oscillator to the electric circuit for actuating the latter when the merchandise carrying the resonant circuit is placed within the field of the oscillator, whereby to indicate the presence of the resonant circuit on the merchandise being stolen.

4. Apparatus for actuating an electric circuit for detecting stolen merchandise, said apparatus comprising an oscillator reactive to a single tuned resonant circuit to change the potential of said oscillator, means forming a resonant circuit tuned to the frequency of the oscillator, a tag adapted to be removably secured to the merchandise, the resonant circuit being concealed within the tag, the oscillator being positioned so that the merchandise must pass through the oscillator field, and means connecting the oscillator to the electric circuit for actuating the latter when the merchandise carrying the resonant circuit is placed Within the field of the oscillator, whereby to indicate the presence of the resonant circuit on the merchandise being stolen.

5. Apparatus for actuating an electric circuit for operating an electrically actuated alarm for detecting stolen merchandise, said apparatus comprising an oscillator For example,

reactive to a single tuned resonant circuit to change the potential of said oscillator, means forming a resonant circuit tuned to the frequency of the oscillator, a tag adapted to be removably secured to the merchandise, the resonant circuit being concealed within the tag, the oscillator being positioned so that the merchandise must pass through the oscillator field, and means connecting the oscillator to the electric circuit for actuating the latter when the merchandise carrying the resonant circuit is placed within the field of the oscillator, whereby to operate the alarm and indicate the presence of the resonant circuit on the merchandise being stolen.

6. Apparatus for actuating an electric circuit, said apparatus comprising, in combination, a plurality of electric switches arranged in series in said electric circuit, electrical actuating means for each switch, an electric circuit for each actuating means, a plurality of oscillators each reactive to a different tuned resonant circuit to change the potential of said oscillator, a plurality of electrical conductors each forming a resonant circuit tuned to the frequency of one of the oscillators, and means connecting each oscillator to a different switch actuating means for actuating the latter when the resonant circuits are placed Within the field of the oscillators.

7. Apparatus for actuating an electric circuit, said apparatus comprising, in combination, a plurality of electric switches arranged to series in said electric circuit, electrical actuating means for each switch, an electric circuit for each actuating means, a plurality of oscillators each reactive to a difierent tuned resonant circuit to change the potential of said oscillator, a plurality of electrical conductors each forming a resonant circuit tuned to the frequency of one of the oscillators, electrically non-conductive container means carrying the resonant circuit concealed therein, and means connecting each oscillator to a different switch actuating means for actuating the latter when the resonant circuits are placed Within the field of the oscillator.

8. In combination with apparatus for detecting stolen merchandise wherein the apparatus includes electrical means reactive to a single tuned resonant circuit to develop a change in electric potential to indicate the presence of said resonant circuit, a tag adapted to be removably secured to the merchandise and comprising a laminated body of electrically non-conductive material, and an electrical conductor secured within the laminated body, the electrical conductor being proportioned to form said tuned resonant circuit.

9. In combination with apparatus for detecting stolen merchandise wherein the apparatus includes electrical means reactive to a single tuned resonant circuit to develop a change in electric potential to indicate the presence of said resonant circuit, a tag adapted to be removably secured to the merchandise and comprising a laminated body of electrically non-conductive material, the tag being perforated transversely to divide the tag in two detachable sections, and an electrical conductor secured within one of said sections of the laminated body, the electrical conductor being proportioned to form said tuned resonant circuit.

References Cited in the file of this patent UNITED STATES PATENTS 1,855,569 Chireix Apr. 26, 1932 1,971,549 Woodward Aug. 28, 1934 2,150,440 Hargreaves Mar. 14, 1939 2,294,751 Harrison et al. Sept. 1, 1942 2,325,927 Wilbur Aug. 3, 1943 2,368,953 Walsh Feb. 6, 1945 2,411,247 Cohen Nov. 19, 1946 

